The invention relates generally to coatings for golf balls, and more particularly, to golf balls with oriented particles applied to any of a number of golf ball layers.
The history of golf ball development has gone very far from wound golf balls to solid two piece golf balls and multi-layer golf balls. Rubber cores gradually replaced wound cores because of quality consistency and performance benefit such as reducing of driver spin for longer distance.
Multi-layer golf balls with layers made of thermoplastic material such as ionomer materials brought golf ball technology to the next level. Typically, thin layers of different materials fused together added extra features such as lower spin off the tee but increasing spin around the green. For example, one of the layers may be a hard ionomer in a mantle layer while a soft elastomer material forms the layer for outer cover. Thin layers of ionomer layers were typically used because ionomer has relatively low resilience, particularly when compared to the rubbers typically used to form the core or the layers of the core.
Flying distance is an important index used to evaluate the performance of a golf ball. Flying distance is affected by three main launch condition factors: initial velocity”, “spin rate”, and “launch angle”. Initial velocity is one of the primary physical properties affecting the flying distance of the golf ball. The coefficient of restitution (COR) is an alternate parameter of initial velocity of the golf ball, and the temperature will affect the COR. The COR is generally defined as the ratio of velocity of an object before and after an impact. A COR of 1 is a perfect elastic collision where no energy is lost due to the collision, and a COR of 0 is a perfect inelastic collision, where all of the energy is dissipated during the collision.
The spin rate of a ball is measured in two main ways, as these different types of spin have different impacts on the flight of the ball. The spin of the ball against the direction of flight is known as “back spin”. Any spin to the ball that is oriented at an angle to the direction of flight is “side spin”. Back spin generally affects the distance of the ball's flight. Side spin generally affects the direction of the ball's flight path.
The spin rate of the ball generally refers to the speed that the ball turns about an axis through the center of the ball. The spin rate of the ball is typically measured in revolutions per minute. Because the spin of the ball generates lift, the spin rate of the ball directly impacts the trajectory of the ball. A shot with a high spin rate flies to a higher altitude than a ball with a low spin rate. Because the ball flies high with high spin, the overall distance traveled by a ball hit with excessive spin is less than an ball hit with an ideal amount of spin. A ball hit with insufficient spin will not generate enough lift to increase the carry distance, resulting in a serious loss of distance. Therefore, hitting a ball with the ideal amount of spin can maximize the distance traveled by the ball.
In addition to affecting the shape of the flight path and/or trajectory of a ball, the spin of a golf ball can also affect the run of the ball, i.e., the distance a ball rolls once the ball hits the ground. Balls with a high spin rate stop sooner than balls hit with a low spin rate. In other words, the run of the ball is lower with a high-spin ball than with a low-spin ball. Therefore, on shots where control is more important than distance, such as approach shots, a high spin is generally preferred.
While a golfer's club and technique play large roles in providing spin to the ball, the ball itself has characteristics that affect the spin rate of the ball. A ball with a soft cover material, such as balata, will achieve a greater level of back spin than a ball with a hard cover. However, balls with soft cover materials are generally more expensive, less durable, and more difficult to play than balls with harder covers. Balls with hard cover materials, such as Surlyn®, are less expensive, but average golfers may find the spin on such balls hard to maximize or difficult to control.
Therefore, there is a need in the art for balls that provide controllable levels of spin.